It is often necessary due to various spinal disorders to surgically correct and stabilize spinal curvatures, or to facilitate spinal fusion. Numerous systems for treating spinal disorders have been disclosed.
One method involves a pair of elongated members, typically spinal rods, longitudinally placed on the posterior spine on either side of spinous processes of the vertebral column. Each rod is attached to various vertebrae along the length of the spine by way of pedicle screws. The pedicle screws each may include a body having a U-shaped rod-receiving channel for receiving a portion of the longitudinal spinal rod therein. Moreover, the body often interacts with a locking cap to clamp and secure the position of the spinal rod within the rod-receiving channel.
To facilitate insertion of the spinal rod into the rod-receiving channels and to provide additional flexibility in the positioning of the spinal rods and the pedicle screws, pedicle screws have been developed wherein the body is pivotable with respect to the bone anchor (commonly known as polyaxial pedicle screws).
It is desirable to develop a pedicle screw that is simple for a surgeon to use, provides for polyaxial rotation and is able to securely mount the rod to the selected vertebra.